tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Pvpanic Device Support
4 *
5 * Copyright (C) 2013 Fujitsu.
6 * Copyright (C) 2018 ZTE.
7 * Copyright (C) 2021 Oracle.
8 */
9
10#include <linux/io.h>
11#include <linux/kernel.h>
12#include <linux/kexec.h>
13#include <linux/mod_devicetable.h>
14#include <linux/module.h>
15#include <linux/platform_device.h>
16#include <linux/types.h>
17#include <linux/cdev.h>
18#include <linux/list.h>
19
20#include <uapi/misc/pvpanic.h>
21
22#include "pvpanic.h"
23
24MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
25MODULE_DESCRIPTION("pvpanic device driver ");
26MODULE_LICENSE("GPL");
27
28static struct list_head pvpanic_list;
29static spinlock_t pvpanic_lock;
30
31static void
32pvpanic_send_event(unsigned int event)
33{
34 struct pvpanic_instance *pi_cur;
35
36 spin_lock(&pvpanic_lock);
37 list_for_each_entry(pi_cur, &pvpanic_list, list) {
38 if (event & pi_cur->capability & pi_cur->events)
39 iowrite8(event, pi_cur->base);
40 }
41 spin_unlock(&pvpanic_lock);
42}
43
44static int
45pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
46 void *unused)
47{
48 unsigned int event = PVPANIC_PANICKED;
49
50 if (kexec_crash_loaded())
51 event = PVPANIC_CRASH_LOADED;
52
53 pvpanic_send_event(event);
54
55 return NOTIFY_DONE;
56}
57
58static struct notifier_block pvpanic_panic_nb = {
59 .notifier_call = pvpanic_panic_notify,
60 .priority = 1, /* let this called before broken drm_fb_helper */
61};
62
63int pvpanic_probe(struct pvpanic_instance *pi)
64{
65 if (!pi || !pi->base)
66 return -EINVAL;
67
68 spin_lock(&pvpanic_lock);
69 list_add(&pi->list, &pvpanic_list);
70 spin_unlock(&pvpanic_lock);
71
72 return 0;
73}
74EXPORT_SYMBOL_GPL(pvpanic_probe);
75
76void pvpanic_remove(struct pvpanic_instance *pi)
77{
78 struct pvpanic_instance *pi_cur, *pi_next;
79
80 if (!pi)
81 return;
82
83 spin_lock(&pvpanic_lock);
84 list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
85 if (pi_cur == pi) {
86 list_del(&pi_cur->list);
87 break;
88 }
89 }
90 spin_unlock(&pvpanic_lock);
91}
92EXPORT_SYMBOL_GPL(pvpanic_remove);
93
94static int pvpanic_init(void)
95{
96 INIT_LIST_HEAD(&pvpanic_list);
97 spin_lock_init(&pvpanic_lock);
98
99 atomic_notifier_chain_register(&panic_notifier_list,
100 &pvpanic_panic_nb);
101
102 return 0;
103}
104
105static void pvpanic_exit(void)
106{
107 atomic_notifier_chain_unregister(&panic_notifier_list,
108 &pvpanic_panic_nb);
109
110}
111
112module_init(pvpanic_init);
113module_exit(pvpanic_exit);